Dementia has been recognised as a major public health problem worldwide, with a prevalence of around 6.5% in the over-65s in England (e.g. Matthews F et al. Lancet 2013). Assessment at memory clinics includes clinical and cognitive assessment and structural imaging with MRI as standard. Among the additional tests (e.g. DAT SPECT, amyloid PET), FDG PET is probably the most versatile, able to provide differential diagnostic information and an indication of the degree of severity of abnormalities, but is often used late in the patient pathway. Its addition only after a patient has been discussed at a multi-disciplinary (team) meeting (MDM) with incomplete data leads to delays of typically 3-4 months before optimised management.

Patient care could be much improved, and patient pathways accelerated, by increased diagnostic confidence earlier in the management pathway. Current barriers to using FDG PET early on are organisational (the need for a second imaging appointment), financial (cost of the tracer, exam and reading), and regulatory (radiation burden ~5 mSv/study). We propose to address all of these points via a single-scan, ~35-min, PET-MR assessment with massively reduced patient doses (at least 10-fold; potentially even 100-fold).

Preliminary work:

Over the past six months and in close discussions with the industrial partner, we have determined that:

Clear patterns (e.g. unilateral temporal lobe hypometabolism) can be easily detected at levels as low as 1 to 5% of the standard dose using MR-assisted PET image reconstruction (Figure 1)

Post-smoothing of up to about 11 mm FWHM is compatible with clinically useable images